KR102112838B1 - Optical film and display device comprising the same - Google Patents

Abstract

The optical film according to an embodiment of the present invention includes a base film having a base film having first and second lens pattern portions protruding from each other in one direction from one surface of the substrate, and a cover film disposed on the base film, The first lens pattern portion includes a first surface, a first side surface extending from one side of the first surface to one surface of the substrate, and a second side surface extending from the other side of the first surface to one surface of the substrate, and the second lens pattern portion comprises It includes a second side, a third side extending from one side of the second side to one side of the substrate, and a fourth side extending from the other side of the second side to one side of the substrate, from the contact point of the second side and the first side to the third side The angle between the imaginary line connecting the side surface and the contact point of one surface of the substrate and the surface of the substrate is less than 50 degrees, the shapes of the first and second side surfaces of the first lens pattern portion are symmetrical to each other, and the third and The shape of the fourth side Can be symmetrical.

Description

Optical film and display device including the same {OPTICAL FILM AND DISPLAY DEVICE COMPRISING THE SAME}

The present invention relates to an optical film and a display device including the same.

The importance of the display device is increasing with the development of multimedia. In response to this, various types of display devices such as a liquid crystal display (LCD) and an organic light emitting display (OLED) are used.

Among them, the liquid crystal display device includes a thin film transistor, a pixel electrode, and a common electrode, and may include liquid crystal interposed between both substrates facing each other. Examples of the operation mode of the liquid crystal layer include a twisted nematic mode or an electrically controlled birefrigence mode. The birefringent control (electrically controlled birefrigence) mode, a vertical alignment (Vertical Alignment) method, OCB (Optically Compensated) method, IPS (In-Plane Switching) method and the like. As an example of a driving method of a liquid crystal display, when an electric field is formed between the pixel electrode and the common electrode, an angle of liquid crystals in the liquid crystal layer with respect to the pixel electrode or the common electrode is arranged to be smaller than 90 degrees to realize an image that gradually becomes brighter. have.

Recently, research has been conducted to expand a viewing angle from a side surface in addition to the front viewing angle of the liquid crystal display device.

The problem to be solved by the present invention does not include a portion that does not affect the visibility improvement, by forming a distance or angle between a plurality of lens pattern portions under a predetermined condition to improve the visibility, the optical can improve the side viewing angle It is to provide a film and a display device including the same.

The problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

An optical film according to an embodiment of the present invention for solving the above problems includes a base film, a base film having first and second lens pattern portions spaced apart from each other in one direction from one surface of the substrate; And a cover film disposed on an upper portion of the base film, wherein the first lens pattern portion has a first surface, a first side extending from one side of the first surface to one surface of the substrate, and the other side of the first surface. It includes a second side surface extending to one surface of the substrate, the second lens pattern portion is a second surface, a third side surface extending from one side of the second surface to one surface of the substrate and the other side of the second surface An angle formed by a virtual line connected to the contact point between the third side surface and one surface of the substrate from a contact point between the second side surface and the first surface and a fourth side surface extending to one surface of the substrate is 50 Less than

The shapes of the first and second side surfaces of the first lens pattern portion are symmetrical to each other, and the shapes of the third and fourth side surfaces of the second lens pattern portion are symmetrical to each other.

The shapes of the first and second side surfaces of the first lens pattern portion and the shapes of the third and fourth side surfaces of the second lens pattern portion may be straight lines.

The shapes of the first and second side surfaces of the first lens pattern portion and the shapes of the third and fourth side surfaces of the second lens pattern portion may be curved.

The shapes of the first and second side surfaces of the first lens pattern portion and the shapes of the third and fourth side surfaces of the second lens pattern portion may be either convex or concave.

One surface of the substrate connecting between the second side surface and the third side surface in the second direction may contact the cover film.

The optical film according to another embodiment of the present invention includes a cover film having first and second intaglio pattern portions spaced apart from each other, and the first intaglio pattern portion is provided on the first surface and one side of the first surface. It includes a first side extending to one side of the cover film and a second side extending from the other side of the first side to the one side of the cover film, wherein the second engraved pattern portion is from the second side and the one side of the second side. And a third side surface extending to one surface of the cover film and a fourth side surface extending from the other side of the second surface to one surface of the cover film, and from the contact point of the second side surface and the first surface to the third side surface. And the angle between the virtual line connecting to the contact point of one surface of the substrate and one surface of the cover film is less than 50 degrees.

The shapes of the first and second side surfaces of the first lens pattern portion are symmetrical to each other, and the shapes of the third and fourth side surfaces of the second lens pattern portion are symmetrical to each other.

The shapes of the first and second side surfaces of the first lens pattern portion and the shapes of the third and fourth side surfaces of the second lens pattern portion may be straight lines.

The shapes of the first and second side surfaces of the first lens pattern portion and the shapes of the third and fourth side surfaces of the second lens pattern portion may be curved.

The shapes of the first and second side surfaces of the first lens pattern portion and the shapes of the third and fourth side surfaces of the second lens pattern portion may be either convex or concave.

One surface of the cover film connecting between the second side surface and the third side surface may be parallel to the other surface.

A display device according to an exemplary embodiment of the present invention includes a display panel; And a base film having first and second lens pattern portions spaced apart from each other on an upper portion of the display panel, and an optical film having a cover film disposed on the base film and having a different refractive index from the base film. The first lens pattern portion includes a first surface, a first side surface extending from one side of the first surface to one surface of the substrate, and a second side surface extending from the other side of the first surface to one surface of the substrate. The second lens pattern portion includes a second surface, a third side surface extending from one side of the second surface to one surface of the substrate, and a fourth side surface extending from the other side of the second surface to one surface of the substrate, and the second surface. The angle between the imaginary line connecting the side surface and the first surface to the contact point of the third side surface and one surface of the substrate and one surface of the substrate is less than 50 degrees.

The shapes of the first and second side surfaces of the first lens pattern portion are symmetrical to each other, and the shapes of the third and fourth side surfaces of the second lens pattern portion are symmetrical to each other.

The shapes of the first and second side surfaces of the first lens pattern portion and the shapes of the third and fourth side surfaces of the second lens pattern portion may be straight lines.

The shapes of the first and second side surfaces of the first lens pattern portion and the shapes of the third and fourth side surfaces of the second lens pattern portion may be curved.

The shapes of the first and second side surfaces of the first lens pattern portion and the shapes of the third and fourth side surfaces of the second lens pattern portion may be either convex or concave.

One surface of the substrate connecting between the second side surface and the third side surface in the second direction may contact the cover film.

The refractive index of the cover film may be greater than that of the base film.

The refractive index of the cover film is 1.53 to 1.57, and the refractive index of the base film may be 1.42 to 1.5.

When the refractive index of the base film is 1.2 to 1.6, and the refractive index of the cover film is greater than the refractive index of the base film and within a range of 1.5 to 2, the angle may be 40 degrees or less.

Details of other embodiments are included in the detailed description and drawings.

According to embodiments of the present invention has at least the following effects.

When used in a display device, an optical film according to an embodiment of the present invention can improve contrast ratio and improve visibility.

In addition, the display device according to the exemplary embodiment of the present invention may provide excellent side viewing angle while implementing excellent front luminance.

The effects according to the embodiments of the present invention are not limited by the contents exemplified above, and more various effects are included in the present specification.

1 is a perspective view showing an optical film according to an embodiment of the present invention.
FIG. 2 is a perspective view showing an embodiment of a base film among the optical films illustrated in FIG. 1.
3 is a perspective view illustrating an embodiment of a cover film among the optical films shown in FIG. 1.
FIG. 4 is a cross-sectional view of the optical film shown in FIG. 1 taken along the direction A-A '.
5 and 6 are views for explaining the effect of the optical film according to an embodiment of the present invention.
7 is a view showing an embodiment of the lens pattern portion of the optical film according to an embodiment of the present invention.
8 is a perspective view showing an optical film according to another embodiment of the present invention.
9 is a cross-sectional view of the optical film shown in FIG. 8.
10 is a cross-sectional view of the base film attached to the optical film shown in FIG. 8.
11 is a perspective view illustrating a display device according to an exemplary embodiment of the present invention.
12 is a cross-sectional view of the display device illustrated in FIG. 11.
13 and 14 are cross-sectional views illustrating the display device illustrated in FIG. 11 in more detail.
15 is a perspective view illustrating a display device according to another exemplary embodiment of the present invention.
16 is a cross-sectional view of the display device illustrated in FIG. 13.

Advantages and features of the present invention, and methods for achieving them will be clarified with reference to embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only the embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention pertains It is provided to completely inform the person having the scope of the invention, and the present invention is only defined by the scope of the claims.

The first, second, etc. are used to describe various components, but these components are not limited by these terms, and are only used to distinguish one component from other components. Therefore, it goes without saying that the first component mentioned below may be the second component within the technical spirit of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a perspective view showing an optical film 10 according to an embodiment of the present invention.

Referring to FIG. 1, the optical film 10 according to an embodiment of the present invention may include a base film 100 and a cover film 200.

The base film 100 may include a first substrate 110 and a plurality of lens pattern portions 120 formed to protrude in one direction from the first substrate 110. Each of the plurality of lens pattern parts 120 is spaced apart from each other and is disposed on the base 110. The plurality of lens pattern parts 120 may include first and second lens pattern parts 121 and 122. This will be described later with reference to FIG. 2.

The cover film 200 may be combined with the base film 100. The cover film 200 may include a plurality of intaglio pattern portions 220 that are engraved in one direction from the second substrate 210 and the second substrate 220. The plurality of engraved pattern parts 220 may have a shape symmetrical to the plurality of lens pattern parts 120 so as to be combined with the plurality of lens pattern parts 120. This will be described later with reference to FIG. 3.

The base film 100 may have a refractive index different from that of the cover film 200. More specifically, the refractive index of the base film 100 may be smaller than the refractive index of the cover film 200. In one embodiment, the difference between the refractive index of the base film 100 and the refractive index of the cover film 200 may be 0.03 to 0.15. have. Through this, the optical film according to an embodiment of the present invention can be applied to a display device described later, thereby increasing front luminance and widening left and right viewing angles.

FIG. 2 is a perspective view showing an embodiment of the base film 100 among the optical films 10 shown in FIG. 1.

Referring to FIG. 2, the base film 110 may include a first substrate 110 and a plurality of lens pattern portions 120 formed to protrude from the first substrate 110. The plurality of lens pattern portions 120 may be formed on the base film 110 to be spaced apart from each other and parallel.

The first substrate 110 may include a material that transmits light. In one embodiment, the first substrate 110 may include a photo-curable resin or a thermo-curable resin. Meanwhile, the first substrate 110 and the plurality of lens pattern parts 120 may be integrally formed in one embodiment, or may be formed of the same material.

The plurality of lens pattern units 120 may include one surface and a curved surface extending from both sides of the one surface. The plurality of lens pattern units 120 may be formed to have one surface parallel to one surface of the first substrate 110 in one embodiment. The plurality of lens pattern parts 120 may include first and second lens pattern parts 121 and 122.

The first lens pattern part 121 may include a first surface 121a, a first side surface 121b, and a second side surface 121c. The first surface 121a of the first lens pattern part 121 may be formed to be parallel to the first substrate 110, but is not limited thereto. In addition, the first side surface 121b of the first lens pattern part 121 may be formed to extend from one side of the first surface 121a to one surface of the first substrate 110. The second side surface 121c of the first lens pattern part 121 may be formed to extend from the other side of the first surface 121a to one surface of the first substrate 110. The first and second side surfaces 121b and 121c may have symmetrical shapes, but are not limited thereto. In addition, the first and second side surfaces 121b and 121c may be curved or straight in cross section.

The second lens pattern part 122 may include a second surface 122a, a third side surface 122b, and a fourth side surface 122c. The second surface 122a of the second lens pattern portion 122 may be formed to be parallel to the first substrate 110, but is not limited thereto. In addition, the third side surface 122b of the second lens pattern portion 122 may be formed to extend from one side of the second surface 122a to one surface of the first substrate 110. The fourth side surface 122c of the second lens pattern portion 122 may be formed to extend from the other side of the second surface 122a to one surface of the first substrate 110. The third and fourth side surfaces 122b and 122c may have symmetrical shapes, but are not limited thereto. In addition, the first and second side surfaces 121b and 121c may be curved or straight in cross section. That is, the first and second lens pattern parts 121 and 122 may have the same shape, length, and height T.

The optical film 10 according to an embodiment of the present invention includes the first contact surface of the first surface 121a and the second side surface 121b of the first lens pattern part 121, and the second lens pattern part 122. 3 When a virtual line (l) connecting a side surface (122b) and a contact point of one surface of the first substrate (110) is drawn, a first angle (θ) between the virtual line (l) and one surface of the first substrate (110) Can be greater than 0 degrees and less than 50 degrees. This will be described with reference to FIG. 4.

Meanwhile, the base film 100 may be formed by molding the resin film on a resin film satisfying a refractive index range of 1.42 to 1.5 using a mold corresponding to the shape of the plurality of lens pattern portions 120. However, it is not limited thereto, and may be formed through an imprinting method or the like.

3 is a perspective view showing an embodiment of the cover film 200 of the optical film 10 shown in FIG. 1.

The cover film 200 may include a second substrate 210 and a plurality of engraved pattern parts 220. The plurality of engraved pattern parts 220 may have a shape corresponding to each other of the plurality of lens pattern parts 120 so as to be combined with the plurality of lens pattern parts 120.

Meanwhile, the cover film 200 may be formed by applying and curing a resin satisfying a refractive index range of 1.53 to 1.57 on the surface on which the plurality of lens pattern portions 120 are formed. However, the present invention is not limited thereto, and may also be formed through a method of adhering it to the base film 100 after preparing the cover film 200 having a plurality of engraved pattern portions 220.

Meanwhile, the resin constituting the cover film 200 may include a UV-curable resin or a thermosetting resin, and may include an acrylate-based resin. Thereby, the optical film can be manufactured by the curing method as described above. In addition, the base film 100 may include a UV-curable or heat-curable resin in the same way as the cover film 200, and by further including a fluorine-based resin in these resins, it can be adjusted to the refractive index range as described above.

FIG. 4 is a cross-sectional view of the optical film 10 shown in FIG. 1 taken along the direction A-A '.

The optical film 10 according to an embodiment of the present invention includes the first contact surface of the first surface 121a and the second side surface 121b of the first lens pattern part 121, and the second lens pattern part 122. 3 When drawing the virtual line (l) connecting the contact point of the side surface (122b) and one surface of the first substrate 110, the angle between the virtual line (l) and one surface of the first substrate 110 (θ, the angle below ) May be greater than 0 degrees and less than 50 degrees.

The first angle θ may be expressed by Equation 1 below between the refractive index of the base film 100 and the refractive index of the cover film 200.

[Equation 1]

θ = sin ^-1 (L / H * sin (90-sin-1 (1 / L)))

At this time, L is the refractive index of the base film 100, H is the refractive index of the cover film 200.

In one embodiment, when the first angle θ is about 47 degrees or less, the refractive index of the base film 100 may be 1.5, and the refractive index of the cover film 200 may be 1.53. In another embodiment, when the first angle θ is about 40 degrees or less, the refractive index of the base film 100 may be 1.42, and the refractive index of the cover film 200 may be 1.57. However, the present invention is not limited thereto, and the refractive index of the base film 100 may be, for example, 1.2 to 1.6. In addition, the refractive index of the cover film 200 is greater than the refractive index of the base film 100 and may be within a range that satisfies the conditions of 1.5 to 2 simultaneously.

Meanwhile, the third side surface 122b and the first base material 110 of the second lens pattern portion 122 from the contact points of the second side surface 121c of the first lens pattern portion 121 and one surface of the first base material 110 ), The distance S to the contact point of one surface may be proportional to the height T of the first and second lens pattern parts 121 and 122, and is inversely proportional to the tangent value of the first angle θ. can do. More specifically, the distance S may be greater than a value obtained by dividing the height T of the first and second lens pattern parts 121 and 122 by tan θ. That is, the following equation (2) can be satisfied.

[Equation 2]

S> T / tan θ

On the other hand, the distance (S) is the distance (x) from the center of the first lens pattern portion 121 to the side surface (w) from the center of the first lens pattern portion 121 to the second lens pattern portion 122 (x As a value minus), Equation 3 below may be satisfied.

[Equation 3]

y = -m (x-x0) + y0

. y0 =

}{x0 =

. y0 =

}

(@y = 0)x =

(@y = 0)

S = x-w

At this time, x and y are virtual function (l) as a function, and x0 and y0 are virtual line (l) and the first lens pattern part 121 contacting the first surface 121a of the contact point as coordinates. to be. That is, the distance S between the first and second lens pattern parts 121 and 122 may be determined according to the first angle θ between the virtual line 1 and one surface of the first substrate 110.

Accordingly, the first and second lens pattern parts 121 and 122 provide light emitted at a relatively small angle relative to a vertical side to a side having a relatively large angle. When the optical film 10 according to the embodiment is applied, side visibility may be improved.

5 and 6 are views for explaining the effect of the optical film 10 according to an embodiment of the present invention. 5 is a graph showing a portion of a light emitted from a specific angle in a display device including an optical film according to the prior art, according to the incident angle. 6 is a graph showing a forward / lateral gamma curve.

In the configuration of the optical film according to the prior art, the elliptical lens unit changes the direction of light emitted in the normal direction of the display panel to change the direction out of the normal, and changes some of the light provided in the direction outside the normal to the normal direction It was possible to improve color shift by inducing color mixing.

However, referring to FIG. 6, it can be seen that the potion size of the side 60 degrees incident component (C1) is relatively larger than that of the side 33 to 52 degrees incident component (C2). This means that in the case of the incident components of the side 33 to 52 degrees (C2), the contribution to improving visibility is very low compared to the case of the incident component of the side 60 degrees (C1).

Therefore, in the optical film 10 according to an embodiment of the present invention, the first and second lens pattern parts 121 and 122 have first and second surfaces 121a and 122a, respectively, thereby improving visibility. It may not include the part with low contribution to.

In the case of a display device using an optical film according to the related art, as the side black luminance higher than the front black luminance is coupled to the front, the black luminance rises and the contrast ratio (CR) decreases. Particularly, in the optical film according to the related art, as part of the side luminance is coupled to the front regardless of gradation, the white luminance is lowered and the black luminance is increased to decrease the contrast ratio (CR). At this time, one of the factors for increasing the black luminance is the presence of the upper portion of the lens unit and the distance between the lens units.

Accordingly, in the case of the optical film 10 according to an embodiment of the present invention, unlike the optical film according to the prior art, the upper region does not exist, and the distance between the plurality of lens pattern parts 120 and the lens pattern part ( Contrast ratio CR may be improved when the angle between 120) satisfies a predetermined condition.

Table 1 below is a table showing the degree of enhancement of the contrast ratio (CR) of the optical film according to the prior art and the optical film 10 according to an embodiment of the present invention.

Prior art The present invention white 440.9 456.6 black 0.1225 0.1065 CR 3599 4289

Referring to Table 1, it can be seen that the optical film 10 according to an embodiment of the present invention has an improved contrast ratio (CR) compared to the optical film according to the prior art.

Furthermore, referring to FIG. 6, it can be seen that the optical film 10 according to an embodiment of the present invention improves visibility due to coupling of a gamma curve closer to the front.

That is, as the optical film 10 according to an embodiment of the present invention includes a plurality of lens pattern portions 120 that remove the upper region of the lens portion that hardly affects the visibility improvement, the contrast ratio CR It is further improved and visibility can be improved due to the coupling of the gamma curve.

7 is a view showing an embodiment of the lens pattern portion 120 of the optical film 10 according to an embodiment of the present invention.

Referring to FIGS. 2 and 7, the shape of the side surface of the lens pattern unit 120 is not particularly limited as long as one surface of the first substrate 110 is opposite to one surface. That is, it may be a convex shape as shown in (a) and (b) of Figure 7, or may be a straight shape as shown in (c). Furthermore, it may have a concave shape as in (d). In addition, as shown in FIGS. 7A and 7B, the length of one surface of the lens pattern unit 120 is not particularly limited.

8 is a perspective view showing an optical film 11 according to another embodiment of the present invention. 9 is a cross-sectional view of the optical film 11 shown in FIG. 8. However, descriptions overlapping with those described in FIGS. 1 to 7 will be omitted.

8 and 9, the optical film 11 according to another embodiment of the present invention may include a cover film 200. That is, unlike the optical film 10 described with reference to FIGS. 1 to 7, the optical film 11 according to another embodiment of the present invention may not include the base film 100.

The cover film 200 may include a plurality of intaglio pattern portions 220 that are engraved from the second substrate 210 and the second substrate 210 and spaced apart from each other. The plurality of intaglio pattern portions 220 may include one surface and a curved surface extending from both sides of the one surface. The cover film 200 may have a refractive index of 1.53 to 1.57 in one embodiment.

The plurality of intaglio pattern portions 220 may include first and second intaglio pattern portions 221 and 222. The first and second engraved pattern portions 211 and 222 may be one of polygonal, semicircular, and semi-elliptical cross-sections in one embodiment.

The first engraved pattern portion 221 may include a first surface 221a, a first side surface 221b, and a second side surface 221c. The first surface 221a of the first engraved pattern portion 221 may be formed to be parallel to the second substrate 210, but is not limited thereto. In addition, the first side surface 221b of the first engraved pattern portion 221 may be formed to extend from one side of the first surface 221a to one surface of the second substrate 210. The second side surface 221c of the first engraved pattern portion 221 may be formed to extend from the other side of the first surface 221a to one surface of the second substrate 210. The first and second side surfaces 221b and 221c may have symmetrical shapes, but are not limited thereto. In addition, the first and second side surfaces 221b and 221c may be curved or straight in cross section.

The second engraved pattern portion 222 may include a first side 222a, a third side 222b, and a fourth side 222c. The first surface 222a of the second engraved pattern portion 222 may be formed to be parallel to the second substrate 210, but is not limited thereto. In addition, the third side surface 222b of the second engraved pattern portion 221 may be formed to extend from one side of the second surface 222a to one surface of the second substrate 210. The fourth side surface 221c of the second engraved pattern portion 222 may be formed to extend from the other side of the first surface 222a to one surface of the second substrate 210. The third and fourth side surfaces 222b and 222c may have symmetrical shapes, but are not limited thereto. In addition, the third and fourth side surfaces 222b and 222c may be curved or straight in cross section. That is, the first and second engraved pattern portions 221 and 222 may have the same shape, length, and height.

The optical film 11 according to another embodiment of the present invention includes a first contact 221a and a second side 221b of the second engraved pattern portion 221, and a second engraved pattern portion 222. When drawing the virtual line l2 connecting the contact points of the three side surfaces 222b and one surface of the second substrate 210, the second angle θ2 between the virtual line l2 and one surface of the second substrate 210 Can be greater than 0 degrees and less than 50 degrees. In addition, the distance from the contact point of the second side 222b and the first side 222a of the cover film 200 to the contact point of the third side 222c and one side of the cover film 200 is the first and second intaglio. The height of the pattern portions 221 and 222 may be greater than a value divided by the tangent value of the second angle θ2.

Meanwhile, at least one of the depth and the width of the plurality of engraved pattern units 220 may be 10 μm or more. In more detail, the aspect ratios of the plurality of engraved pattern portions 220 may range from 0.5 to 1.6. At this time, the aspect ratio of the plurality of intaglio pattern portions 220 is a value obtained by dividing the depth of the intaglio pattern portions 220 by width. Accordingly, when the plurality of intaglio pattern portions 220 satisfy the above-described aspect ratio range, and the cover film 200 satisfies the above-described refractive index range, the optical film 11 according to an embodiment of the present invention is displayed When applied to the device, the luminance in the front direction can be increased, and the viewing angle in the left and right directions can be increased.

10 is a cross-sectional view of the base film 111 attached to the optical film 11 shown in FIG. 8.

Referring to FIG. 10, the optical film 11 according to another embodiment of the present invention may be combined through the base film 111 and the adhesive 20. The adhesive 20 may be formed in a region in which the intaglio pattern portion 220 is not formed in the cover film 200. Accordingly, a phenomenon in which light provided from the display panel 300 (see FIG. 11) is distorted or scattering can be prevented. Meanwhile, an air layer may be filled between the cover film 200 and the base film 111, that is, inside the plurality of engraved pattern portions 220. The air layer has a refractive index substantially close to one. Accordingly, when the optical film 11 according to another embodiment of the present invention is applied to a display device, the difference between the refractive index of the cover film 200 and the refractive index of the air layer, and the aspect ratio range of the plurality of engraved pattern portions 220 Thus, the viewing angle in the left and right directions can be increased while increasing the luminance in the plane direction.

11 is a perspective view illustrating a display device according to an exemplary embodiment of the present invention. 12 is a cross-sectional view of the display device illustrated in FIG. 11. However, portions overlapping with those described in FIGS. 1 to 10 will be omitted.

11 and 12, a display device according to an exemplary embodiment of the present invention may include an optical film 10 and a display panel 300.

The optical film 10 may be disposed on the display panel 300. The optical film 10 may include a base film 100 and a cover film 200. The base film 100 may include a first substrate 110 and a plurality of lens pattern portions 120 formed to protrude in one direction from the first substrate 110. The base film 100 may have a refractive index different from that of the cover film 200. More specifically, the refractive index of the base film 100 may be smaller than the refractive index of the cover film 200. In one embodiment, the difference between the refractive index of the base film 100 and the refractive index of the cover film 200 may be 0.03 to 0.15. have. Referring to FIG. 2 together, the first lens pattern part 121 may include a first surface 121a, a first side surface 121b, and a second side surface 121c. The second lens pattern part 122 may include a second surface 122a, a third side surface 122b, and a fourth side surface 122c. The optical film 10 includes a contact point between the first surface 121a and the second side surface 121b of the first lens pattern part 121, and the third side surface 122b and the first surface of the second lens pattern part 122. When drawing the virtual line l connecting the contact point of one surface of the substrate 110, the first angle θ between the virtual line 1 and one surface of the first substrate 110 is greater than 0 degrees and greater than 50 degrees Small and can be greater than 0 degrees.

The display panel 300 may include a plurality of pixel units P as a portion displaying an image. The plurality of pixel units P may be arranged in a matrix form on the display panel 300 in one embodiment. That is, the plurality of pixel units P may be constantly arranged in a horizontal direction and a vertical direction according to a predetermined rule. Each of the plurality of pixel units P may form one pixel displaying an image, and each pixel may represent one of red, green, and blue. The display panel 300 may be formed of a plasma display panel (PDP), a plasma address liquid crystal display panel (PALC), a liquid crystal display (LCD), and an organic light emitting diode (OLED) panel. However, for convenience of description, the case where the display panel 300 is a liquid crystal panel will be described as an example.

The optical film 10 and the display panel 300 may be laminated through a coupling member (not shown). The bonding member may be an adhesive or an adhesive, and may include at least one of acrylic adhesive, silicone adhesive, urethane adhesive, polyvinyl butyral adhesive, ethylene-vinyl acetate adhesive, polyvinyl ether and melamine resin. . Meanwhile, the bonding member is not necessarily limited to an adhesive or an adhesive, and may include a resin component. Accordingly, the optical film 10 and the display panel 300 may be laminated through a thermal curing method or the like.

The display panel 300 may include an upper polarizing plate 700, a first substrate 500, a liquid crystal layer 600, a second substrate 400, and a lower polarizing plate 800. The liquid crystal layer 600 may be disposed between the first substrate 500 and the second substrate 400.

The upper polarizing plate 700 may include one surface on which the optical film 10 is stacked and the other surface opposite thereto. The upper polarizing plate 700 may be attached to a position where a viewer views an image in a display device according to an embodiment of the present invention. An optical film 10 may be stacked on one surface of the upper polarizing plate 700. The transmission axes of the polarizers of the upper polarizing plate 700 and the lower polarizing plate 800 may be orthogonal or parallel to each other. Meanwhile, the lower polarizing plate 800 may include one surface on which the second substrate 400 is stacked and the other surface opposite thereto. Each of the upper polarizing plate 700 and the lower polarizing plate 800 may include a polarizer protective film and a polarizer.

The first substrate 500 may include one surface on which the upper polarizing plate 700 is stacked and the other surface opposite thereto. The first substrate 500 may be a TFT (Thin Film Transistor) array substrate. A liquid crystal driving electrode, a wiring pattern, a thin film transistor element, and an alignment layer may be formed on the first substrate 500. In one embodiment, a thin film transistor and a pixel electrode including a gate electrode, a gate insulating layer, a semiconductor layer, a resistive contact layer, and a source / drain electrode may be included on a substrate made of a transparent insulating material such as glass or plastic.

The second substrate 400 may include one surface on which the liquid crystal layer 600 is stacked and the other surface opposite thereto. A color filter, a common electrode, an alignment layer, etc. may be formed on a surface of the second substrate 400 facing the first substrate 500, and a black matrix (BM) may be formed as necessary. More specifically, the second substrate 400 may include a black matrix for preventing light leakage on a lower surface of a substrate made of a transparent insulating material such as glass or plastic, a color filter of red, green, and blue, and a common electrode.

Plastic substrates that can be used for the first substrate 500 and the second substrate 400 can be used for displays, such as PET (polyethylene terephthalate), PC (polycarbonate), PI (polyimide), PEN (polyethylene naphthalate), PES (polyether) It may be a plastic substrate such as sulfone), PAR (polyarylate) and COC (cycloolefin copolymer), but the present invention is not limited thereto. In addition, the first substrate 500 and the second substrate 400 may include a flexible material.

On the other hand, if one embodiment of the display panel 300 is a liquid crystal display panel, the operation mode may be a twisted nematic mode or an electrically controlled birefrigence mode. Further, the birefringent control (Electrically Controlled Birefrigence) mode may include a vertical alignment (Vertical Alignment) method, an OCB (Optically Compensated) method, an IPS (In-Plane Switching) method. In the TN mode, if there is no voltage difference between the pixel electrode and the common electrode, that is, the electric field generating electrode, and the electric field is not applied to the liquid crystal display panel, the liquid crystal of the liquid crystal display panel has a long axis direction of the first substrate 500 and the second substrate 400 ) Can be arranged parallel to the surface. In addition, the structure may have a twisted 90 ° spirally from the first substrate 500 to the second substrate 400. At this time, the polarization of the linearly polarized light may change due to retardation due to anisotropy of the refractive index of the liquid crystal while passing through the liquid crystal layer 600 of the liquid crystal display panel. When the dielectric anisotropy (Δε) and chiral pitch of the liquid crystal or the depth of the liquid crystal display panel, that is, the cell gap, is adjusted, the linear polarization direction of light passing through the liquid crystal display panel is rotated by 90 °. I can make it.

The display device according to an embodiment of the present invention may further include a backlight unit 400 disposed under the display panel 300.

When the display panel 300 is a liquid crystal panel in one embodiment, since it corresponds to a passive pixel, a separate light source is required. Accordingly, a backlight unit 400 that supplies light may be disposed under the display panel 300. When the backlight unit 400 supplies light, the display panel 300 may display various images. This will be described later with reference to FIGS. 13 and 14.

13 and 14 are cross-sectional views illustrating the display device illustrated in FIG. 11 in more detail. However, when the display device according to the exemplary embodiment of the present invention includes an edge type backlight unit, it will be referred to as 400a (see FIG. 13) and the direct type backlight unit will be referred to as 400b (see FIG. 14). .

Referring first to FIG. 13, a display device according to an exemplary embodiment of the present invention may include an edge backlight unit 400a. Accordingly, the display device according to an exemplary embodiment of the present invention includes at least one light source 900 and a light guide plate disposed on a side surface of the light source 900 to guide light emitted from the light source 900 upwards; LGP) 1000, and may include optical plates 1200 and 1300 positioned between the light source 900 and the display panel 300. Also, a reflective sheet 1100 may be disposed on the lower surface of the light guide plate 1000. The light source 900 may be disposed on at least one side of the light guide plate 1000. For the light source 900, for example, an LED (Light Eimitting Diode), a CCFL (Cold Cathode Fluorescent Lamp), an HCFL (Hot Cathode Fluorescent Lamp), or an EEFL (External Electrode Fluorescent Lamp) may be used. The light guide plate 1000 may move light emitted from the light source 900 through total internal reflection, and may be reflected and reflected through a scattering pattern formed on the bottom surface of the light guide plate 1000 to emit light upward. Also, the reflective sheet 1100 may be disposed under the light guide plate 1000 to reflect light emitted downward from the light guide plate 1000 to the top. An optical plate 1200. 1300 may be disposed on the light guide plate 1000. The optical plates 1200 and 1300 may include a diffusion sheet 1200 and a prism sheet 1300. The diffusion sheet 1200 diffuses a part of the light traveling from the light source 900 and transmits it to the display panel 300 disposed on the diffusion sheet 1200, and sends another part back to the bottom of the diffusion sheet 1200 Can be reflected. Diffusion sheet 1200 is an example of PMMA (Polymethyl methacrylate), PS (Polystyrene), PC (Polycarbonate), COC (cyclo-olefin copolymers), PET (Polyethylene terephthalate), PBT (Polybutyleneterephtalate), plastic material alloy (alloy) ) May be formed of one material selected, but is not limited thereto. On the other hand, the optical plate (1200, 1300), if necessary, a micro lens array film, a lenticular lens film, or the like may be additionally used, and the arrangement relationship may be changed.

Next, referring to FIG. 14, a display device according to an exemplary embodiment of the present invention may include a direct type backlight unit 400b. The display device according to an embodiment of the present invention may include at least one light source 900 and optical plates 1200 and 1300 disposed between the light source 900 and the display panel 300. The display device according to an exemplary embodiment of the present invention uniformly disperses light emitted from the lower light source 900 by the upper diffusion sheet 1200 and condenses light by the prism sheet 1300 to display the panel 300 You can proceed to.

Although not separately illustrated, the backlight unit 400a described in FIG. 12 and the backlight unit 400b described in FIG. 13 may be accommodated by the bottom chassis, and the display panel 300 is seated on the middle frame and the upper top chassis Can be fixed by.

15 is a perspective view illustrating a display device according to another exemplary embodiment of the present invention. 16 is a cross-sectional view of the display device illustrated in FIG. 13. The display device according to another embodiment of the present invention differs from the display device according to an embodiment of the present invention in that the optical film 11 includes only the cover film 200.

The display device according to another embodiment of the present invention may include an optical film 11 having a cover film 200, a display panel 300, and a backlight unit 400.

The cover film 200 may include a plurality of intaglio pattern portions 220 that are engraved from the second substrate 210 and the second substrate 210 and spaced apart from each other. The cover film 200 may have a refractive index of 1.53 to 1.57 in one embodiment. The plurality of intaglio pattern portions 220 may include first and second intaglio pattern portions 221 and 222. The first engraved pattern portion 221 may include a first surface 221a, a first side surface 221b, and a second side surface 221c. The second engraved pattern portion 222 may include a first side 222a, a third side 222b, and a fourth side 222c. The optical film 11 has a contact point between the first surface 221a and the second side surface 221b of the second engraved pattern portion 221, and the third side surface 222b and second surface of the second engraved pattern portion 222. When drawing the virtual line l2 connecting the contact point of one surface of the substrate 210, the second angle θ2 between the virtual line l2 and one surface of the second substrate 210 is greater than 0 degrees and greater than 50 degrees It can be small. In addition, the distance from the contact point of the second side 222b and the first side 222a of the cover film 200 to the contact point of the third side 222c and one side of the cover film 200 is the first and second intaglio. The height of the pattern portions 221 and 222 may be greater than a value divided by the tangent value of the second angle θ2.

Meanwhile, at least one of the depth and the width of the plurality of engraved pattern units 220 may be 10 μm or more. In more detail, the aspect ratios of the plurality of engraved pattern portions 220 may range from 0.5 to 1.6. At this time, the aspect ratio of the plurality of intaglio pattern portions 220 is a value obtained by dividing the depth of the intaglio pattern portions 220 by width. Accordingly, when the plurality of intaglio pattern portions 220 satisfy the above-described aspect ratio range, and the cover film 200 satisfies the above-described refractive index range, the optical film 11 according to an embodiment of the present invention is displayed When applied to the device, the luminance in the front direction can be increased, and the viewing angle in the left and right directions can be increased.

Although the embodiments of the present invention have been described with reference to the accompanying drawings, a person skilled in the art to which the present invention pertains may be implemented in other specific forms without changing the technical spirit or essential features of the present invention. You will understand. Therefore, it should be understood that the above-described embodiments are illustrative in all respects and not restrictive.

10, 11: optical film;
100: base film;
110: first description;
120: lens pattern portion;
210: second description
220: engraved pattern portion;
200: cover film;
300: display panel;
400: backlight unit

Claims (18)

A base film having first and second lens pattern portions protruding in a first direction from one surface of the substrate and spaced from each other in a second direction perpendicular to the first direction; And
It includes a cover film disposed on top of the base film,
The first lens pattern portion includes a first surface, a first side surface extending from one side of the first surface to one surface of the substrate, and a second side surface extending from the other side of the first surface to one surface of the substrate,
The second lens pattern portion includes a second surface, a third side surface extending from one side of the second surface to one surface of the substrate, and a fourth side surface extending from the other side of the second surface to one surface of the substrate,
The angle formed by the virtual line connected from the contact point of the second side surface and the first surface to the contact point of the third side surface and the substrate and one surface of the substrate is less than 50 degrees,
The shapes of the first and second side surfaces of the first lens pattern portion are symmetrical to each other,
The shapes of the third and fourth side surfaces of the second lens pattern portion are symmetrical to each other. According to claim 1,
An optical film having a shape of the first and second side surfaces of the first lens pattern portion and a shape of the third and fourth side surfaces of the second lens pattern portion. According to claim 1,
The shape of the first and second side surfaces of the first lens pattern portion and the shape of the third and fourth side surfaces of the second lens pattern portion are curved optical films. According to claim 3,
The shape of the first and second side surfaces of the first lens pattern portion and the shape of the third and fourth side surfaces of the second lens pattern portion are either convex or concave. According to claim 1,
One surface of the substrate connecting between the second side surface and the third side surface in the second direction is an optical film contacting the cover film. It includes one side and the other side facing each other, and includes cover films having first and second lens pattern portions spaced apart from each other on the one side,
The first lens pattern portion includes a first surface, a first side surface extending from one side of the first surface to one surface of the cover film, and a second side surface extending from the other side of the first surface to one surface of the cover film. ,
The second lens pattern portion includes a second surface, a third side surface extending from one side of the second surface to one surface of the cover film, and a fourth side surface extending from the other side of the second surface to one surface of the cover film. ,
The angle between the imaginary line connected to the contact point of the second side surface and the first surface to the contact point of the third side surface and the cover film and one surface of the cover film is less than 50 degrees,
The shapes of the first and second side surfaces of the first lens pattern portion are symmetrical to each other,
The shapes of the third and fourth side surfaces of the second lens pattern portion are symmetrical to each other. The method of claim 6,
An optical film having a shape of the first and second side surfaces of the first lens pattern portion and a shape of the third and fourth side surfaces of the second lens pattern portion. The method of claim 6,
The shape of the first and second side surfaces of the first lens pattern portion and the shape of the third and fourth side surfaces of the second lens pattern portion are curved optical films. The method of claim 8,
The shape of the first and second side surfaces of the first lens pattern portion and the shape of the third and fourth side surfaces of the second lens pattern portion are either convex or concave. The method of claim 6,
One surface of the cover film connecting between the second side and the third side is an optical film parallel to the other surface. Display panel; And
A base film disposed on an upper portion of the display panel, a base film protruding in a first direction from one surface of the base, and having first and second lens pattern portions spaced from each other in a second direction perpendicular to the first direction; It is disposed on top of the base film and includes an optical film having a cover film having a different refractive index from the base film,
The first lens pattern portion includes a first surface, a first side surface extending from one side of the first surface to one surface of the substrate, and a second side surface extending from the other side of the first surface to one surface of the substrate,
The second lens pattern portion includes a second surface, a third side surface extending from one side of the second surface to one surface of the substrate, and a fourth side surface extending from the other side of the second surface to one surface of the substrate,
The angle formed by the virtual line connected from the contact point of the second side surface and the first surface to the contact point of the third side surface and the substrate and one surface of the substrate is less than 50 degrees,
The shapes of the first and second side surfaces of the first lens pattern portion are symmetrical to each other,
The shape of the third and fourth side surfaces of the second lens pattern portion is symmetrical to each other. The method of claim 11,
The shape of the first and second side surfaces of the first lens pattern portion and the shape of the third and fourth side surfaces of the second lens pattern portion are straight display devices. The method of claim 11,
The shape of the first and second side surfaces of the first lens pattern portion and the shape of the third and fourth side surfaces of the second lens pattern portion are curved display devices. The method of claim 13,
The shape of the first and second side surfaces of the first lens pattern portion and the shape of the third and fourth side surfaces of the second lens pattern portion is one of a convex or concave shape. The method of claim 11,
A display device having one surface of the substrate connecting between the second side surface and the third side surface in the second direction contacts the cover film. The method of claim 11,
A display device having a refractive index of the cover film greater than that of the base film. The method of claim 11,
The display device has a refractive index of 1.53 to 1.57, and a refractive index of the base film of 1.42 to 1.5. The method of claim 11,
When the refractive index of the base film is 1.2 to 1.6, and the refractive index of the cover film is greater than the refractive index of the base film and within a range of 1.5 to 2, the angle is 40 degrees or less.

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